Thermionic electron emission from diamond by nano-seconds laser heating

Investigating a vacuum thermionic emission behavior of a CVD diamond film on silicon substrate is reported. Under vacuum conditions and subjected to a moderate voltage bias, the bare silicon and diamond coated silicon samples show emission current pulses synchronized with excitation nano seconds 532 nm Nd:YAG pulsed laser. Nano second laser is applied to back side of the substrate and the emission site is screened from laser excitations. As increasing the pulse laser intensity, peak emission current increases monotonically. The Arrhenious plot of the peak emission current and the pulse laser intensity relationship follows Richardson´s thermionic emission equation in the bare silicon sample. The diamond-coated sample shows two activation energies: one is the same as silicon and the other shows zero activation energy.